I would not bother to sweat his neck. He is what he is. He is a bit long in the back but has a nice shoulder with the point of shoulder set correctly high so the Humerus lays at a good angle. This allows hgim to pull his knees level and tuck over a fence.
He has good bone. Pasterns are a bit short but if he has stayed sound jumping a good bit, then it is not important. Hocks are a tad high and legs look like they might be just a bit camped under.. again, if he is sound and working solidly, it is not important. While the peak of croup would lead one to believe he is butt hight, he is actually pretty level. Root of neck to point of buttock angle shows that.
Nice horse and you have done well with him.
How old is he? You mention him doing things for "years" which would lead one to believe he is smooth mouth.. maybe in his teens?
There is something about the outside of a horse that is good for the inside of a man. ~Winston Churchill
) Dinosaur Horse Trainer